Template bushing and locking means

ABSTRACT

A bushing having a bore for guiding a drill bit and means for locking the bushing to a template or jig is disclosed. The bushing, which is particularly suitable for thin templates or jigs, has an exterior chamfer on one end for engaging a countersunk aperture in the template and left-hand threads disposed about its other end. A lock ring, adaptable for engaging the left-hand threads on the bushing rigidly couples the bushing to the template. The torque of a drill bit engaging the bushing bore tends to tighten the lock ring to the template; thus, the bushing remains secure during use.

United States Patent [1 1 Bethke [451 Oct. 30, 1973 [54] TEMPLATEBUSHING AND LOCKING 3,108,500 10/1963- Merriman 408/241 B AN 3,158,0451l/l964 Sller 408/115 B 2,920,509 l/l960 Bennett 408/72 B Inventor: DaleL. Bethke,2924 Mesa Drive,

West Covina, Calif. 91791 Filed: July 28, 1971 Appl. No.: 166,770

Related US. Application Data Continuation-impart of Ser. No. 848,420,Aug. 8, 1969, abandoned.

US. Cl. 408/72 B, 408/241 B Int. Cl 8235 49/02 Field of Search 408/72 B,115 B,

= References Cited UNITED STATES PATENTS Primary Examiner-Francis S.l-lusar Attorney-Spensley, l-lorn & Lubitz [57] ABSTRACT A bushinghaving a bore for guiding a drill bit and means for locking the bushingto a template or jig is disclosed. The bushing, which is particularlysuitable for thin templates or jigs, has an exterior chamfer on one endfor engaging a countersunk aperture in the template and left-handthreads disposed about its other end. A lock ring, adaptable forengaging the lefthand threads on the bushing rigidly couples the bushingto the template. The torque of a drill bit engaging the bushing boretends to tighten the lock ring to the template; thus, the bushingremains 'secureduring use.

4.Claims, 11 Drawing Figures Patented 0a. 30, 1973 3,768,918

2 Sheets-Sheet 1 445 A. fizz /(.5

INVENTOR.

Patented Oct. 30, 1973 2 Sheets-Sheet 2 WWI] INVENTOR.

BY v Q 6 7% ATTO/P/VEVS TEMPLATE BUSHING AND LOCKING MEANS This is acontinuation-in-part application of Ser. No. 848,420, filed on Aug. 8,1969 and now abandoned.

BACKGROUND OF THE INVENTION for coupling and rigidly holding a drillbushing to atem plate or jig. All of the existing template bushing andfastening means have disadvantages which make them difficult to use orlimit the applications in which they may be used. This is particularlytrue for those bushings which are made for use with thin jigs ortemplates. While the thin templates have the advantage of being lessexpensive to fabricate and easier to handle, they present a moredifficult problem for attaching a bushing and maintaining it at thedesired location since the length of the aperture through the templateinto which the bushing must be secured, is considerably smaller than theaperture length in a thick template or jig.

In U.S. Letters Patent No. 1,237,143, one prior art method is disclosedfor securing a bushing to a thin template or jig. In this patent, astrap, which is riveted at its ends to the template, is used forsecuring a bushing to the template. The strap engages the tool receivingend of the bushing, thereby securing the bushing to the template. One ofthe disadvantages to this method is that it requires the drilling andcountersinking of at least two additional holes into which the rivetsare disposed. Since it is difficult to accurately locate the rivetreceiving holes with the bushing aperture, this method of securing abushing often results in an improperly aligned or located bushing.Additionally, the bushing may become cocked during its use since thestrap does not provide adequate lateral support. Another disadvantage ofthis bushing and locking means is the fact that the bushingis difficultto remove and typically, the bushing and strap, after removal, are notusable.

In US. Letters Patent No. 2,920,509, another prior art device forsecuring abushing to a thick template is described, In this disclosure aring or collar, which rests on the template, clinches the tool receivingend of the bushing, securing it to the template. One problem with thisdevice is that it does not always prevent the bushing from rotatingrelative to the template while the bushing is guiding a tool. Also,excessive clinching pressure may distort the thin template.Additionally, each bushing is only adaptable for use with a singletemplate thickness; thus, a plurality of bushings must be stocked if thebushings are to be used with templates of different thickness. Removalof this type of locking means results in the destruction of the lockingmeans and often damage to the bushing itself.

Another bushing which is used with thin templates includes a flared endwhich fits into an aperture in the template or jig. Typically, thebushing is hammered into the template and can become readily cocked dueto improper hammering. Where the bushing is not perfectly flared thebottom flared extension becomes an obstruction. In removing the bushing,it often must be drilled out and it is generally not reusable and thehole is distorted.

, Another prior art method of securing a bushing to a thin templateincludes the use of a self-clinching press fit bushing. The'bushing ispressed into an aperture in the template and it requires the use ofexpensive installation equipment. The bushing tends to become cocked dueto improper initial alignment. Additionally, the edges of the bushingreceiving aperture in the template become distorted after the bushing isremoved and often the template and bushing are not reusable.

In US. Letters Patent No. 3,108,500, a method for securing a bushing ina thick template is disclosed which includes a snap ring. This methodhas the disadvantage of not always satisfactorily securing the bushingto the template. The snap ringmay not be reused once it is removed fromthe bushing.

Other locking means and bushings often referred to as slip removablebushings which require the drilling of apertures into the template otherthan the aperture into which the bushing is placed are disclosed in US.Letters Patents Nos. 3,244,034 and 3,336,822.

Additionally, other locking means and bushings referred to as fixed slipbushings which also require apertures in the template other than theaperture for receiving the bushing are disclosed in US. Letters PatentNo. 2,997,902 and British Patent No. 546,926.

SUMMARY OF THE INVENTION A template or jig drill bushing and lockingmeans is described which comprises a bushing which guides a drillthrough a template and an outer locking ring for securing the bushing tothe template. The bushing contains a chamfered base end which is made toengage a countersunk or dimpled bore in a thin plate or template. Theother end, or top end, of the bushing comprises a left-hand thread. Acylindrical lock ring with inner threads adaptable for engaging thematching threaded bushing secures the bushing to the template by pullingthe angular or chamfered end tightly within the dimpled or countersunkaperture, or against a flat surface surrounding the aperture where nocountersink or dimple is present. The torque exerted on the bushing whenthe bushing is guiding a drill bit tends to tighten the lock ringagainst the template, thus causing the bushing to remain rigidly securedor to become more secured to the template during use.

It is an object of the present invention to provide a template bushingand locking means which may be readily installed in a template withoutbending or otherwise damaging the template and wherein the bushingbecomes more secured to the template with use.

Another object of the present invention is to insure that a drill isguided at a predetermined angle relative to a template, typically at anangle of It is a further object of the present invention to provide alocking means for the drill bushing wherein a single locking means maybe used with a plurality of bushings having different inside diameters.I

It is still another object of the present invention to provide a drillbushing and locking means which are reusable, readily removable andreplaceable.

It is still another object of the present invention to provide a drillbushing and locking means wherein a single drill bushing and lockingmeans may be utilized with templates of different thicknesses.

Another object of the present invention is to, provide a bushing thatmay be used with an aperture made with standard drills or punches.

Another object of the present invention is to provide a bushing which isself-aligning and automatically aligns itself with the template or jig.

Still another object of the present invention is to provide a bushingand locking means which does not require the use of any aperture in atemplate, except the bushing receiving aperture.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of thedrill bushing, lock ring and section of a template or jig prior to theirassembly;

FIG. 2 is a cross-section of a template illustrating the countersunk ordimpled aperture into which the drill bushing is placed;

FIG. 3 illustrates the drill bushing and its left-hand threads engagingan aperture in a template;

FIG. 4 illustrates a drill bushing engaging an aperture of a templatewhere the bushing is secured to a template by a lock ring;

FIG. 5 illustrates a perspective view of a drill bit engaging a drillbushing where the bushing is secured to a template; the bushing, lockring and template are illustrated in a sectional view;

FIG. 6 is a cross-sectional view of a drill bushing and lock ringengaging a thick template; 1

FIG. 7 is .a partially cutaway view illustrating a drill bushing, lockring and template wherein a flange of the drill bushing extends belowthe surface of the template;

FIG. 8 is an assembly drawing which illustrates a tool which may beutilized to remove bushings built in accordance with the presentinvention from a template; and

FIGS. 9a, 9b and )0 illustrate in cross-sectional views drill bushingsand lock rings engaging templates of different thickness.

DETAILED DESCRIPTION OF THE INVENTION The drill bushing, locking meansand template or jig are illustrated in FIG. 1 as bushing 11, lock ring12 and template 10, respectively. The bushing 11 and lock ring 12 areillustrated prior to their assembly into template 10. The bushing 11illustrated in FIGS. 1, 3 and 4, is a generally cylindrical memberhaving a bore 25 axially disposed through its body. The bore 25 isadaptable and used for guiding a drill bit when the bushing is securedto a template or jig. An exterior enlargement such as chamfer 14, whichis disposed peripherally about the exterior of one end of bushing 11,has a maximum diameter greater than the diameter of the remaintier ofbushing 11. Thus, when bushing 11 is placed in an aperture such ascircular aperture 18 whose diameter is approximately equal to thediameter of bushing 11, the bushing is unable to completely pass throughthe aperture since the chamfer 14 will engage or abut one surface of thetemplate l0. Left-hand threads 15 are disposed exteriorly about theperiphery of the other end of the bushing. A kn'url or serration 16 isexteriorly disposed about or defined by bushing 11 between the left-handthreads 15 and the chamfer 14. The maximum diameter of the serration 16is larger than or approximately equal to the maximum diameter of thelefthand thread-s 15. The bushing 11 may be made from steel, aluminum orother metals and may be hardened, utilizing commonly known techniques.

Lock ring 12 comprises a cylindrical sleeve most clearly seen in FIGS.1, 4 and 5. Threads 19 are disposed about the inner surface of lock ring12 at one end, said threads being'adaptable for cooperatively engagingthe left-hand threads 15 of bushing 11. The lock ring 12 has an annularsurface 23 which is adaptable for engaging a surface of template 10 whenthe lock ring is made to engage the threads of bushing 11 as illustratedin FIG. 4. The inside diameter of the nonthreaded interior of lock ring12 should be counterbored larger than the maximum diameter of serration16 so that the lock ring may be readily threaded onto bushing 11 asillustrated in FIG. 4. The lock ring may be made of aluminum or othermetals utilizing commonly known techniques. A pair of notches 17 arediametrically cut into one end of lock ring 12. The notches are utilizedfor engaging an adjusting wrench, such as the tool shown in FIG. 8, sothat lock ring 12 may be tightened or loosened onto bushing 11.

The drill bushing 11 is typically utilized in conjunction with a thinmetal plate or jig such as template 10 illustrated in FIGS. 1 through 5.An aperture, such as circular aperture 18, is disposed through template10 at the location where it is desired to locate the drill bushing onthe template. The aperture 18 may be countersunk or dimpled, as isillustrated by countersink 13 of FIG. 2. The dimple or countersink 13should be adaptable for engaging chamfer 14 as is illustrated in FIG. 3,such that the bottom of bushing 11 is flush with or does not protrudebelow the surface of template l0 and become an obstruction. The bushing11 is pressed into aperture 18 and partially prevented from rotatingwithin the aperture by serrations 16 which tend to grip the portion oftemplate l0 defining aperture 18.

After the bushing 11 has been placed within aperture 18, lock ring 12 isthreaded onto the left-hand threads 15 of bushing 11 such that surface23 of lock ring 12 engages a surface of template 10 as is shown in FIG.4. As the lock ring 12 is tightened, the chamfer 14 securely engagesdimple or countersink l3, firmly holding the bushing 11 in place ontemplate 10.

Referring to FIG. 5, bushing 11 is illustrated secured to the template10 by mearrs of lock ring 12. A drill bit 24 is illustrated engaging thebushing. Since the bore 25 of the bushing communicates with the aperture18, the

drill bit 24 is able to drill into a workpiece beneath the template asit is guided by the bushing 11.

The direction of rotation of drill bit 24 is indicated by arrow 20 inFIG. 5. This direction of rotation is the standard direction of rotationfor drill bits. As bit 24 turns within bushing 11, the friction betweenthe drill bit 24 and the bore 25 of the bushing 11 may cause bushing 11to turn or rotate in the direction indicated by arrow 22. Since bushing11 has a left-handthread which is engaged by lock ring 12, rotation ofbushing 11 in the direction of arrow 22 causes lock ring 12 to moretightly grip bushing 11. Thus, as the bushing is used to guide a drillbit, the rotation of the drill bit tends to cause the bushing to be morerigidly gripped by the lock ring and template. Unlike other drillbushings, which tend to loosen with use, the present drill bushingbecomes more secure on the template with use.

It is, of course, within the scope of the present invention to utilize aright-hand thread on the bushing 11 where the direction of rotation of abit is opposite to the standard direction illustrated by arrow 20.

The serrations 16 on drill bushing 11 tend to also prevent the rotationof the bushing within aperture 18. The

serrations are not necessary for the operation of the bushing but are anadded feature which tends to prevent the rotation of the bushing andsecure the bushing to the template while the lock ring is placed on thebushing.

With reference to FIG. 4, if the annular surface 23 is perpendicular tothe axis of threads 19 of lock ring 12, which it is in the presentlypreferred embodiment, tightening of the lock ring on the bushing meanscauses the bushing to align with aperture 18 of template 10. With theprior art bushings, the operation of securing the bushing to thetemplate often results in a misalignment between the bushing andtemplate. In the present invention, thetightening of the bushing and itsuse tend to align rather than misalign the bushing with the aper ture inthe template.

With the bushing and lock ring herein disclosed, the bushing l 1 andlock ring 12 may be readily re-used simply by unscrewing the lock ringfrom the bushing and then by removing the bushing from the template.These operations are not destructive in nature and will not result inany damage to the bushing or lock ring.

It should be further noted that with the template and locking meansherein described, a single bushing and lock ring may be utilized withtemplates of different thicknesses. This is so since the inside diameterof the end of, lock ring 12 which abuts template is greater than thediameter of serrations 16.

Another feature of the present invention is that a single lock ring maybe utilized with a plurality of bushings. With reference to FIG. 4, thebore 25 may be of any size provided that its diameter is less than thediameter of bushing 11 and the bushing may still be used with a singlelock ring 12. This is anadvantage over some prior art bushings whereinnumerous different locking means are required for different sizebushings.

Referring'to FIG. 6, an alternate embodiment of the present invention isillustrated wherein the bushing 31 and lock ring 32, which aresubstantially similar in construction to the bushing and lock ringillustrated in FIGS. 1, 4 and 5, are coupled to a thick template 3. Thedrill bushing 31 includes a bore 34 for guiding a drill or other tool, achamfer 35 for engaging a countersink in template 30, and threads 33which cooperatively engage threads on lock ring 32. As in the previouslydescribed embodiment, left-hand threads are utilized in order that thelock ring 32 does not'loosen with use. It can be readily seen from FIG.6 that by the use of a lock ring 32, which is generally angular inshape, and of shorter length than the lock rings illustrated in FIGS. 1,4 and 5, a drill bushing built in accordance with the present inventionmay be utilized on a thicker template such as template 30.

In FIG. 7 an alternate embodiment of the present invention isillustrated, which again includes a lock ring 44 which may be similar tothe lock ring illustrated in FIGS. 1, 4 and 5 and a bushing 43 whichincludes a bore 45.- Bushing 43 is similar in construction to the drillbushing discussed-in conjunction with FIGS. 1, 3, 4 and 5 except thatthe end of the bushing opposite the tool entrant end includes a flange46. This flange has a larger diameter than the aperture into which thebushing 43 is placed. The outer surface of locking means 44 includes anouter knurled surface which improves manual tightening and loosening oflock ring 44 onto the bushing 35 and template 41. In this embodiment nocountersink or dimple is needed in the template since the bushing isheld in place by the flange 46 and lock ring 40. The flange 46 serves asa support for the template 41; thus, when the template 41 is placed upona workpiece, the template maybe supported by a plurality of suchbushings engaging the template and the template will remain above theworkpiece. By the use of this embodiment and by machining the lowersurface and edges of flange 46 so that they are smooth and contain norough edges, the workpiece is protected from the surface 47' of thetemplate.

Referring to FIG. 8, a tool which may be utilized to remove the lockrings from the bushings and template is illustrated, which comprises alock ring insertion tip 53 and an elongated'handle. The elongatedcylindrical handle contains threads 52 at one end, which may be standardright-hand threads, for engaging threads 54 of tip 53. Also, the handleincludes a knurled surface 48 and a hexagonally shaped section 49. Anaperture 50 is disposed perpendicular to the cylindrical axis of thehandle at the end of the handle opposite threads 52 and is adaptable forreceiving a rod such as rod 51. The member 53, which is of a generallycylindrical shape, defines a cavity 56 and a pair of diametricallydisposed ribs 55 adaptable for engaging notches such as notches 17 shownin "FIG. 1.

-When it is necessary to remove a lock ring, which includes notches, thehandle is threadingly engaged with member 53 and the cavity 56 is placedover the lock ring such that the ribs 55 engage the notches, such asnotches 17 of FIG. 1. The lock ring may then be loosened by manuallyturning the handle, or by placing a wrench on the hexagonal section 49,or by rotating the tool by use of the rod 51. With the use of this toolit has been found that the lock rings may be readily and quickly removedfrom the bushing and template with little effort and without damage.

The lock rings and bushings illustrated in FIGS. 1, 4, 5, 6 and 7 mayalso be used for positioning workpieces on a template. It has been foundthat when a plurality of bushings and lock rings are fastened to atemplate or other metal member, at predetermined positions, the toolentrant portion of the bushing and the lock ring form guide posts whichmay be used to align a workpiece on a metal member, template or jig. Thedisclosed lock ring and bushing are particularly adaptable in thisapplication, since they may be accurately positioned and since the lockring tends to squarely align the bushing onto a jig, template or othermetal memher.

In FIG. 9a, a bushing 71 is secured to a relatively thick template 63 bylock ring 66. As previously discussed, the lower end of ring 66 engagesthe surface of template 63. In FIG. 9b, bushing 72 is engaging atemplate 64 of medium thickness. Note that the lower end of lock ring 67includes a cylindrically shaped end 69 which has an inside diameterlarger than the diameter of the serration on the bushing 67. The lowersurface of end 69 engages surface 61 of template 64, thereby securingthe upper end of bushing 72 to template 61. In FIG. 9c bushing 73 issecured to a thin template by lock ring 68. Note that the lock ring 68includes a longer cylindrically shaped end than end 69 of lock' ring 67.This longer end 70 allows the upper end of the bushing 73 to be securedto the surface 62 of template 65. Thus, by manufacturing lock ringshaving ends of different lengths a single bushing may be secured totemplates having different thicknesses.

I claim: 1. In combination, a thin plate member or jig and a lockabledrill bushing means comprising:

a thin plate member having upper and lower parallel surfaces withaperture means extending from said upper to said lower surfaces forretaining a removable -bushing therebetween, said aperture means havingupper and lower perimeters which are flush with the respective upper andlower plate surfaces;

reuseable bushing means removably disposed within said aperture meansincluding an elongated body of predetermined length, one end of saidbody being enlarged for preventing said end from passing from the lowersurface of said plate member to the upper surface of said plate member,said body being formed with external left-hand threads adjacent the freeend of said body for receiving locking means thereon and an inner borefor guiding a drill through said body and underlying plate member, saidbody projecting substantially outwardly from said upper surface relativeto the overall length of said body, said reuseable bushing means havingmeans provided on its external surface at the lower portion thereof forfrictional engagement with said thin plate member; and

reuseable locking means with internal threads cooperatively removablyengageable with said left-hand external threads on said bushing body forsecurely positioning said bushing against said thin plate member, saidlocking means being tightened by the rotational movement of a drill asit is guided within said bushing means.

2. The combination of claim 1 wherein said bushing body enlargement isflanged.

1. In combination, a thin plate member or jig and a lockable drillbushing means comprising: a thin plate member having upper and lowerparallel surfaces with aperture means extending from said upper to saidlower surfaces for retaining a removable bushing therebetween, saidaperture means having upper and lower perimeters which are flush withthe respective upper and lower plate surfaces; reuseable bushing meansremovably disposed within said aperture means including an elongatedbody of predetermined length, one end of said body being enlarged forpreventing said end from passing from the lower surface of said platemember to the upper surface of said plate member, said body being formedwith external left-hand threads adjacent the free end of said body forreceiving locking means thereon and an inner bore for guiding a drillthrough said body and underlying plate member, said body projectingsubstantially outwardly from said upper surface relative to the overalllength of said body, said reuseable bushing means having means providedon its external surface at the lower portion thereof for frictionalengagement with said thin plate member; and reuseable locking means withinternal threads cooperatively removably engageable with said left-handexternal threads on said bushing body for securely positioning saidbushing against said thin plate member, said locking means beingtightened by the rotational movement of a drill as it is guided withinsaid bushing means.
 2. The combination of claim 1 wherein said bushingbody enlargement is chamfered and said thin plate member aperture iscountersunk for receiving said bushing body enlargement chamfer suchthat said thin plate member has a flush surface when said bushing bodyis disposed therein.
 3. The combination of claim 1 wherein said bushingbody includes serRation means adjacent the enlarged end for frictionallyengaging said thin plate member aperture.
 4. The combination of claim 1wherein said bushing body enlargement is flanged.